A metal box found in a building on Soi Phahon Yothin 24 and mistakenly thought to contain highly radioactive cobalt-60 forced an evacuation of people living nearby on Thursday.
The box was found late in the afternoon in a two-storey commercial building under renovation on Soi Phahon Yothin 24, sub-soi 2-1, in Chatuchak district.
Pimchaya Surasarapan, the building’s caretaker, said she found the container which contains a label of hazardous substance and alerted police as she feared it might pose a health risk to her and other people.
An initial inspection indicated that the box might contain the hazardous radioactive substance cobalt-60. This forced police and firefighters to evacuate people and to block access around a 200-metre perimeter as a precaution while they waited for experts from the Office of Atoms for Peace (OAP) to check it.
Science and Technology Ministry Pichet Durongkaveroj said the inspection team concluded that what was in the metal container was not cobalt-60 but Iridium-192 (Ir-192), a radioactive isotope, which had expired in 1995 and was no longer dangerous. No leakage was detected from the case.
Ir-192 is used in industrial gauges that inspect welding seams and in medicine to treat certain cancers.
The International Atomic Energy Agency defines Ir-192 as a category-2 radioactive substance. This means the substance can permanently injure a person who handles the radioactive material for minutes to hours, and it can kill people in close proximity within hours to days, according to the agency.
Mr Piochet said possession or import of Ir-192 requires a permit and authorities will regularly check the place where it is kept to ensure safety and consider the licence renewal. Moving the container without permission, like in this case, was illegal, he added.
Ms Pimchaya, who lives on the building’s first floor, said she suspected the container was left inside the building by a South Korean friend of the building’s owner, who died six years ago. The Korean rented the building for some time but rarely came as he spent most time in Rayong. He has left Thailand, she said.
Acting city police chief Sanit Mahathaworn said police will check information on the container’s nameplate to identify and prosecute the owner.
Photo from 199 Phra Ram Radio Center